Want to know what you and Joe Montana have in common? He doesn’t like getting older, either.

“‘At my age’—I hate saying that!” he says, as he describes some modifications he’s made to his workout routine to help manage his arthritis. But aching joints haven’t kept the legendary quarterback from maintaining a still-tough fitness regimen—a relic, he says, from years of equating being healthy and fit with career success. Montana credits his ability to stay active in part to a supplement called Joint Juice, for which he’s been the spokesman for several years. Now Joint Juice is raising money for the Arthritis Foundation with a new mobile app called “Throw With Joe,” a game that lets fans indulge their fantasies of having Montana’s famous arm.

We talked to the Hall of Famer about working out with arthritis, what he wishes he’d done differently as a quarterback, and how he feels when he sees his sons on the football field.

Spry: Tell us about your personal experience with arthritis.

Joe Montana: When you’re playing they’re always telling you, “Well, you got a little arthritis here, or in your shoulder, or your elbow.” My knee was probably the biggest problem because I’d had a number of surgeries on my left knee to clean up cartilage. I finally went to see an orthopedic surgeon here in San Francisco, Dr. Kevin Stone, about something he was doing in the knee joints that was cutting edge at that point. He said, “Look, you’re really not ready for that yet, and I wouldn’t do it till you have to, but I’ve been working on this supplement that I think you should try.” So I tried Joint Juice, and my joints feel a lot better. But it does take some time to start working.

Spry: So you had surgery during your career—do you think you’ll have to have it again eventually?

JM: Not if I can help it! My left knee is pretty far along; I can’t straighten it all the way—it’s to the point where it’s pretty progressed. But I’m not going to have surgery again if I don’t have to.

Spry: What kind of fitness routine are you able to maintain?

JM: I’m still going as hard as I can go six or seven days a week. I try to get 45 minutes to an hour of cardio, a little bit of light lifting. I can’t run, so I’m stuck on the dang bike, or elliptical. I don’t feel like I get as much as I’d like from just walking. So, I decided I’m going to try something new pretty soon.

Spry: Is it hard to stay motivated to work out now that it’s no longer your job? Do you get bored more easily without real competition to drive you?

JM: Well, it is hard, that’s why I need to try something new. I do get bored, especially being inside. I try to run on occasion; I wish I could run a little more. I lift probably five days a week, but nothing heavy; just real light, to maintain muscle tone.

It was especially hard getting motivated when I first retired. I was like, “OK, I’m done with this workout crap!” And then—I don’t know how many months after—I get a letter from Sports Illustrated about the Couples’ Swimsuit Issue. I hid the letter, but my wife found it! And she stays in great shape. She’s had four kids and three months after she’s got a washboard stomach again—that’s not fair! I hate that. So I had to call a friend of mine to get me on a program to lose 19 pounds for the shoot!

You know, I get lazy every now and then. I’m on the road a lot, and like everyone else who travels, it’s hard. You’re in an airplane, you go to meetings, and you get to the hotel and you’re just like “Oh, I just want to have dinner.” But you gotta find ways to stay motivated.

Spry: I think one of the most persistent myths about arthritis is that you can’t work out—when in fact it’s the opposite. Did you ever have times when you thought you were in too much pain, or have you always been able to stay active?

JM: I’ve always been able to keep active. Athletes learn early that there’s a little bit of pain and then there’s an injury. You have to play through it. We see the world a little differently than most. A lot of times most people are hurt and they’re OK with it. We get hurt and we don’t want to be out of work, and we try to get healthy as fast as possible, sometimes to our own dismay. But, I’ve never been to that point yet. When my knee swells up, what do I do? I wrap something around it and keep going, sooner than I should most likely at my age.

Spry: It looks like your sons, Nate and Nick, may be following in your footsteps and pursuing football as a career. What kind of advice would you give to them, especially in terms of your experience with arthritis?

JM: Well, they’ve had a lot of lessons and worked with quarterback coaches, and they meet a lot of professional players who can advise them, too, especially on what supplements to start taking for your joints right away. But nutrition is important, and keeping fit. Don’t lift too much, but you gotta lift enough—especially with the quarterback position, there’s a balance that you need. Some people can lift a lot and play that position, some people can’t. But you gotta do enough to keep up with the physical part of the game.

Spry: Is there anything you wish you’d done differently, in terms of taking care of your body?

JM: Well, I wish I was born about 20 years later so I could make some of the money these guys make! I wish I’d lifted weights a little more, but there’s a fine line. When I got to Kansas City, they made me lift five days a week. I went from weighing between 192 and 195 to 208 and I felt like a slug! I said, “I can’t lift five days a week. I can’t even get my pants on—this is ridiculous.” Then I pulled a hamstring because a guy caught me from behind and I said, “I told you if I was 195 I could’ve gotten away from him!” But I think it’s an individual thing where some guys don’t need to lift as much and some guys need to lift more—and it depends on your position, too.

Spry: Were your kids naturally active growing up, or was that something you had to encourage them to do?

JM: I think we made mistakes early—well, not mistakes. But when we had boys, everyone said, “You’re not going to try to push them into football are you?” So we kind of held back a little bit. And our older one kind of got behind, and he’s been playing catch-up. But overall, playing sports, to me, does two things: Physically it’s a great thing to do, and it teaches our kids lessons at an early age. Especially team sports, where you have to deal with a lot of individuals from different races and religions. It teaches you how to accomplish a goal. It teaches us how to be competitive in life. I think we lose sight sometimes with our kids, with sports that don’t keep score, or it’s always a tie at the end of the game. That’s a shame, because we’re taking something away from them that is taught naturally through sports.

Spry: There’s been a lot of talk about injuries in football lately, and I know it makes a lot of parents nervous. Do you worry about your sons, or does having been there make you more confident about their safety?

JM: It’s something you worry about every time they’re on the field. But I know from being there about the excitement of the game—the ups and the downs and the locker-room and the camaraderie, and everything that goes with it. There’s nothing that’s ever come close to that feeling of being on that field, whether you win or lose. I wish everyone could have the opportunity to just play the game once, on a Sunday afternoon. You would understand why these guys try to play forever.